This invention relates to the field of non-reciprocal electrical coupling devices, and more particularly to isolators utilizing ferrite gyromagnetic elements in which the amount of isolation and the bandwidth are a function of the angle between the longitudinal axes of the conductors.
Isolators, circulators and gyrators of many kinds are known in the art for providing non-reciprocal coupling between two circuits in an electrical apparatus. Possible applications include isolating an antenna from the RF stage of a transmitter, or a VCO from load variations, or between sections of a bandpass filter network. One such isolator, having two conductors adjacent a ferrite disc and in a static magnetic field, is shown in U.S. Pat. No. 4,016,510, assigned to the same assignee as is the present invention. In this device, maximum possible bandwidth was achieved by positioning the two conductors with their main axes at 90.degree. to each other, with one end of each grounded and the ungrounded ends coupled to the respective ends of a neutralizing resistor which was also coupled from the input to the output terminal. Since the bandwidth is determined by the neutralizing element which in that case was non-reactive, and the device was not operated at its magnetic resonance, the bandwidth of the patented device was maximal. While the insertion loss in such a device is fairly low, there are applications wherein it is necessary to reduce even this small loss, and a trade-off of less bandwidth for reduced insertion loss would be advantageous.